An anchor generally comprises several elements including ground engaging means usually in the form of one or more planar or curvilinear surfaces usually termed the fluke or flukes. Various fluke shapes are shown in patents to Danforth U.S. Pat. No. 2,249,546; Danforth U.S. Pat. No. 2,674,968; Bruce U.S. Pat. Nos. 2,711,150, 2,840,029 and 3,024,756, Towne U.S. Pat. Nos. 3,777,695 and 4,134,356; van den Haak U.S. Pat. Nos. 3,015,299 and 3,783,815; Taylor U.S. Pat. Nos. 3,902,446, 3,964,421 and 4,089,288; and Klaren U.S. Pat. Nos. 1,974,933 and 4,024,090.
In association with the fluke surfaces, means are provided to facilitate and maintain the proper engagement of the fluke surfaces with the bottom. Such means are usually termed the crown, which initially lifts the after-end of the anchor to force the fluke surfaces into bottom engagement.
A shank extends forwardly from the crown in advance of the fluke surfaces for attachment to an engaged cable or chain. Shanks have usually been in the form of a heavy, solid rectilinear bar. Various authors have pointed out that, particularly in a harder bottom such as sand, penetration of an anchor into bottom often is limited by the shank which slides over the bottom resisting penetration.
It has long been recognized that deep penetration into the bottom is a prime factor in determining the efficiency of an anchor. If the anchor does not penetrate, then the anchor structure merely slides across the bottom.
To provide stability, one or more elements extending laterally from the fluke or flukes are provided to stabilize the entire anchor structure so that it does not rotate when subject to the pulling action applied to the shank by an attached rode. Such an element is frequently referred to as the stock.
With the advent of flexible shanks for anchor structures, as described in U.S. Pat. No. 4,469,042 issued Sept. 4, 1984 to Robert D. Ogg and pending application Ser. No. 642,338 entitled NOVEL SHANK FOR AN ANCHOR STRUCTURE, modifications have been possible to various anchor elements such as the flukes, crown and even crownless anchor designs so as to permit better bottom penetration and burying capability.